Graph the equation 3x + 4y = 180.

Intellectual development (Perry) scores were determined for 21 students in a first-year, project-based design course. (Recall th

Anit [1.1K]

Answer:

The 99% confidence interval is (3.0493, 3.4907).

We are 99% sure that the true mean of the students Perry score is in the above interval.

Step-by-step explanation:

Our sample size is 21.

The first step to solve this problem is finding our degrees of freedom, that is, the sample size subtracted by 1. So

$df = 21-1 = 20$ .

Then, we need to subtract one by the confidence level $\alpha$ and divide by 2. So:

$\frac{1-0.99}{2} = \frac{0.01}{2} = 0.005$

Now, we need our answers from both steps above to find a value T in the t-distribution table. So, with 20 and 0.005 in the two-sided t-distribution table, we have $T = 2.528$

Now, we find the standard deviation of the sample. This is the division of the standard deviation by the square root of the sample size. So

$s = \frac{0.40}{\sqrt{21}} = 0.0873$

Now, we multiply T and s

$M = 2.528*0.0873 = 0.2207$

Then

The lower end of the interval is the mean subtracted by M. So:

$L = 3.27 - 0.2207 = 3.0493$

The upper end of the interval is the mean added to M. So:

$LCL = 3.27 + 0.2207 = 3.4907$

The 99% confidence interval is (3.0493, 3.4907).

Interpretation:

We are 99% sure that the true mean of the students Perry score is in the above interval.

7 0

3 years ago

Which value of x solves the equation cos x° = sin (20° + x°), where 0 < x < 90? A. 30° B. 35° C. 40° D. 45° E. 55°

daser333 [38]

Answer:

Option B (35°).

Step-by-step explanation:

To solve this question, the trigonometric identity sin x = cos (90-x) is required. It can also be written as cos x = sin (90-x). It can be seen that this identity holds when the two angles are complementary i.e. they sum up to 90 degrees. Therefore, the answer can be determined by substituting all the options one by one in the identity cos x = sin (20+x). If x=30 degrees, then x+20=50 degrees. 30 and 50 are not complementary. If x=35 degrees, then x+20=55 degrees. 35 and 55 are complementary since their sum is 90 degrees. Therefore, B is the correct choice!!!

4 0

3 years ago

1/3=7/21, .. What are the means

gayaneshka [121]

Answer:

Equivelant fractions.

Step-by-step explanation:

Ask your self..

How did the 1/3 become 7/21?

Its very simple multiply 1/3's numerator and denominator by 7

So its going to be.. 1 x 7 = 7

3 x 7 = 21

Therefore, we have 7/21

3 0

2 years ago

cylinder shaped can needs to be constructed to hold 200 cubic centimeters of soup. The material for the sides of the can costs 0

Dafna11 [192]

Answer:

Radius=2.09 cm

Height,h=14.57 cm

Step-by-step explanation:

We are given that

Volume of cylinderical shaped can=200 cubic cm.

Cost of sides of can=0.02 cents per square cm

Cost of top and bottom of the can =0.07 cents per square cm

Curved surface area of cylinder= $2\pi rh$

Area of circular base=Area of circular top= $\pi r^2$

Total cost,C(r)= $0.02\times 2\pi rh+2\pi r^2\times 0.07$

Volume of cylinder, $V=\pi r^2 h$

$200=\pi r^2 h$

$h=\frac{200}{\pi r^2}$

Substitute the value of h

$C(r)=0.02\times 2\pi r\times \frac{200}{\pi r^2}+2\pi r^2\times 0.07$

$C(r)=\frac{8}{r}+0.14\pi r^2$

Differentiate w.r.t r

$C'(r)=-\frac{8}{r^2}+0.28\pi r$

$C'(r)=0$

$-\frac{8}{r^2}+0.28\pi r=0$

$0.28\pi r=\frac{8}{r^2}$

$r^3=\frac{8}{0.28\pi}=9.095$

$r=(9.095)^{\frac{1}{3}}=2.09$

Again, differentiate w.r.t r

$C''(r)=\frac{16}{r^3}+0.28\pi$

Substitute the value of r

$C''(2.09)=\frac{16}{(2.09)^3}+0.28\pi=2.63>0$

Therefore,the product cost is minimum at r=2.09

h= $\frac{200}{\pi (2.09)^2}=14.57$

Radius of can,r=2.09 cm

Height of cone,h=14.57 cm

4 0

3 years ago

Between which two consecutive whole number does the square root of 38 lie

Dahasolnce [82]

So rather than think about how to find the whole numbers, let's try to find the two perfect squares nearest to 38. There is one greater than it and one smaller than it. The square root will lie between the squared value of each. (e.g. 64 is the perfect square, 8 is the squared value i refer to)

6 ,7. 6squared is 36 and 7 squared is 42

therefore 38 lies between these two numbers

5 0

3 years ago

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